1. Field of the Invention
This invention relates generally to an engine assembly for a hybrid electric vehicle utilizing turbo-compounding.
2. Description of the Prior Art
Due to increasing concern over global warming, stringent emissions regulations and the cost of fuel, there is a general drive to increase the efficiency of internal combustion engines.
Hybrids vehicles were introduced to recover energy during vehicle deceleration and then make use of it to accelerate/drive the vehicle or by supplying electrical demand. However this can result in a major increase in cost and weight, whilst this does not recover other forms of waste energy, such as the waste heat down the exhaust.
WO2006/117701 describes an engine unit for a hybrid vehicle comprising a gas turbine mounted in the engines exhaust duct which is mechanically coupled to an electricity generator. The recovered energy may be used, for example, for driving motors or compressing air to boost the engine.
US2007/0151241 discloses an internal combustion engine including an exhaust turbine coupled to a generator and a controller to direct electricity generated to an electric motor or to a power storage device. Thus efficiencies are claimed for the more efficient use of electrical energy generated by the generator run by a turbine, compared to direct mechanical couplings directing the turbine's energy back to a crankshaft.